214 INDUCTIVE AFFINITY. 



equally to be zincous. In the same way if B C be entirely 

 copper, the condition of both its extremities will be chlorous 

 from the action of the acid on the two ends of the zinc ; 

 and consequently the elements of such a circle could have no 

 polarity. 



A circle is represented in Fig. 17, containing three sources 

 of polarizing force. It consists of three alternations of copper 



and zinc symmetrically arranged, and 

 forming three polar elements F A, B C 

 and D E, with three acid columns 

 between these alternations, which 

 form three additional polar elements, 

 A B, C D and E F. The number 



of alternations of copper and zinc, 



2 with acid? may obviously be i ncr eased 



to any extent, and the chemical ac- 

 tion of the acid on the zinc in each alternation is found to 

 increase in a marked manner up to the number of 10 or 12 

 alternations. This increase of the affinity is undoubtedly owing 

 to the favouring inductive action, which the chemical actions at 

 the different points have upon each other. Such a compound 

 circle may be compared to a number of magnets disposed in a 

 circle with their attracting poles together, of which each would 

 have its magnetic intensity exalted by induction from all the 

 rest. When such a circle is broken at any point, all chemical 

 action and polarization cease till contact is again made, and the 

 circuit completed. The polarization, too, being the result of a 

 circular induction involving so many lines or chains of particles, 

 cannot, when once established, be more nor less at any one 

 point in the circuit than at others. The resulting chemical 

 action must therefore be every where equal in the circle, and 

 consequently the same quantity of zinc be dissolved and 

 hydrogen evolved in each acid. 



If any metallic element of this compound circle be broken, 

 and a polarizable liquid be interposed between the metallic 

 extremities so as to complete the circuit, decomposition occurs 

 in that liquid as in the simple interrupted circle (Fig. 12.) 

 The polarizing influence of the compound circle being of high 

 intensity, more numerous and difficult decompositions are 

 effected by means of it, than by the simple circle. The 

 compound voltaic circle is indeed a decomposing instrument 

 of great efficiency. 



